Ceratosaurus nasicornis (S/F)

Disambiguation Links Ceratosaurus nasicornis (IDW-JPR)

The “horned lizard,” so named for the distinctive horn on its snout, was discovered in 1883 and the Cleveland Lloyd Dinosaur Quarry of Utah, and was described by Othniel C. Marsh in 1884. Ceratosaurus lived during the Late Jurassic period from about 153 to 148 million years ago; the type species, C. nasicornis, is known only from North America, but specimens of other species have been found in Portugal. Both parts of its binomial name refer to its horn; Ceratosaurus, of course, means “horned lizard,” while nasicornis means “nose horn.” The type specimen of the dinosaur measures about 5.3 m (17.5 ft) in length, though it is unclear if this animal was fully grown or not; a larger specimen discovered in Utah in the mid-1960s may have been up to 8.7 m (28.8 ft) long. Ceratosaurus had a proportionately large head for the size of its body and small, muscular arms, and osteoderms which ran down its body. In terms of taxonomy, Ceratosaurus belongs to the infraorder Ceratosauria and to the family Ceratosauridae, both of which are named after the animal.

Description

Ceratosaurus is a medium-sized carnivorous theropod, easily distinguished by its vivid coloration and prominent nasal horn. Adults reach lengths of 30.5 feet and grow to be 12 feet tall, noticeably larger than currently-known fossil specimens. Adults may weigh up to one ton. The skull is large for its body size, and its jaws are lined with a row of long blade-like teeth. When its mouth is closed, most of these teeth are hidden, but ten teeth in the front of the upper jaw protrude out of the mouth. The nasal horn is ridge-like and shaped like an equilateral triangle. It is not very sharp, and is roughly a foot tall in adults; it is much thinner from side to side, located on the midline of the snout. The skull of the animal also has small hornlets above its eyes, and small conical osteoderms on its crown. More elongated osteoderms continue in a row down the midline of the animal’s thick neck and all the way down its back to its tail, located above the neural spines. This feature is unique among theropods known in the fossil record. Its eyes are relatively small, with green sclerae and circular black pupils. The nostrils are somewhat large, likely giving it a good sense of smell.

Detail on the face of an adult Ceratosaurus. Note that ten teeth of the upper jaw remain exposed when the mouth is shut.

The body is overall fairly robust, with a thick neck and stocky chest. Even the tail is thick, tapering down to a small point. The arms are small, with four minute fingers on each hand; the legs are thicker and stronger, with three clawed toes on each foot. Its tail is deep from top to bottom, somewhat like a crocodile’s. Its body is more compact than fleet-footed theropods such as Allosaurus, with shorter legs and a low-built torso.

Coloration of the Ceratosaurus is, perhaps, one of its most striking features. The head is a vibrant shade of red, with some whitish stripes near the along the upper lips and slightly darker scales around the eyes. Starting around the neck and going all the way to the tail are gray or black irregular stripes, overlaying the animal’s base coloration. These are most vibrant on the neck, becoming gradually more faded toward the tail; they do not extend to the underbelly. The red coloration of the head also fades over the rest of the body, being replaced with a pale yellow color; its underbelly is even lighter, being almost white. On the tail, the gray stripes become closer together, eventually occupying more space than the light yellow base color.

Growth

The hatchling and juvenile stages of Ceratosaurus have not yet been observed.

Sexual Dimorphism

There is currently no information to distinguish male and female Ceratosaurus. The sex of the animal which appeared in the film is not known.

Habitat
Preferred Habitat

As only one individual has been seen so far, the true preferred habitat of this species is not known; it has been sighted in a heavily forested area near a large river affected by tides. In real life, this animal would have inhabited wetlands, lakes, and floodplains.

Jurassic World: Evolution portrays it as preferring 17,700 square meters of grassland with 4,400 square meters of forest.

Isla Nublar

In 2004, all surviving Ceratosaurus were transported from Isla Sorna to Isla Nublar. They were most likely kept in the island’s northern region, away from the park. Population statistics remain unknown between 2004 and 2018. A report released by the Dinosaur Protection Group on February 4, 2018 stated that Ceratosaurus had gone extinct on the island, making it extinct globally.

Isla Sorna

Sometime between late 1998 and mid-1999, Ceratosaurus was cloned on Isla Sorna by InGen under its new parent company Masrani Global Corporation. These animals were created in violation of the Gene Guard Act. Within nine months of their creation, they were abandoned to roam the island.

On the night of June 19, 2001, one adult Ceratosaurus was seen on the western bank of Isla Sorna’s central channel. It is not known how many animals, if there were more than one, existed on the island.

Known range of C. nasicornis on Isla Sorna as of June 19, 2001

The interference on Isla Sorna by Masrani Global Corporation caused an ecological collapse over the next five years, and in 2004, any surviving Ceratosaurus would have been collected and transported to Isla Nublar.

Behavior and Ecology
Daily Activity

Ceratosaurus has been portrayed as being active at night. However, due to a lack of data, its daily activity patterns cannot be stated with confidence.

Diet and Feeding Behavior

While it is known that Ceratosaurus was a carnivore, its diet has not been portrayed, nor have its feeding behaviors. Its blade-like teeth would be capable of inflicting injury to prey, but as the teeth in the very front of the mouth are the largest, it would not likely be able to tear into prey items with its entire mouth. Instead, it would most likely deliver wounding bites and wait for its prey to weaken.

In real life, Ceratosaurus is believed to have lived near bodies of water and may have been a skilled swimmer. This would allow it to prey on fish, turtles, and other aquatic life. On Isla Sorna, the river where this dinosaur was sighted was home to fish such as bonitos.

Video games have consistently portrayed it as feeding primarily on small to medium animals and carrion, as well as displaying cannibalistic tendencies in Jurassic Park: Operation Genesis. It is portrayed in Jurassic World: Evolution as having a large appetite for its size.

Social Behavior

Only one member of this species has been seen, so no confident conclusions about its social behavior can be made. However, the individual seen was solitary.

Its physical features indicate that it does engage in some degree of social interaction, as its striking pattern would make it poor at camouflaging and its nasal horn is not robust enough to serve any combative purpose.

The game Jurassic Park: Operation Genesis portrayed the animal as comfortable in small groups, but without strong social instincts and a tendency toward cannibalism. This game’s spiritual sequel, Jurassic World: Evolution, portrayed the animal as being less social; it becomes stressed in groups of more than three, and as in the original game, it rarely socializes with others of its kind.

Reproduction

As a dinosaur, this animal would lay eggs to reproduce. However, specific details about its reproductive behaviors are unknown. Its nasal horn, bright facial coloration, and elongated spinal osteoderms all indicate that it would engage in some kind of display behavior, but the nature of such behaviors are unknown.

Vocalizations

Ceratosaurus has been heard to make low growling or gurgling noises when alone, and was heard making a groaning sound when frightened.

The video game Jurassic World: Evolution gives it a range of loud roars which it uses to confront rivals and establish territory.

Ecological Interactions
Ceratosaurus displaying a fear response

While there is a lack of behavioral data on this animal, it is known to share some overlapping territory with the much larger Spinosaurus. On one occasion, it smelled dung from this carnivore and immediately retreated from the area, suggesting an antagonistic relationship between this animal and its larger, stronger, and more aggressive neighbor.

The video game Jurassic World: Evolution portrays it as preferring a solitary life with few other species nearby. It is a host to the bacterium Campylobacter, which can sometimes cause the animal to become sick with campylobacteriosis. This bacterium is common in modern birds, inhabiting up to 100% of some poultry in real life.

Interactions with Humans

Ceratosaurus is, perhaps, one of the least aggressive and most docile carnivorous dinosaurs. It has only been recorded interacting with humans once in the films, on which occasion it investigated a small group of humans including Dr. Alan Grant, Paul Kirby, and Amanda Kirby. The animal showed no signs of aggression, sniffed them, and retreated into the forest upon smelling Spinosaurus dung on them. It has been suggested that it was discouraged from eating them by the smell, but during the encounter it did not make any attempt to attack; instead, the animal simply appeared to be curious.

However, the video game Jurassic Park: Operation Genesis and its sequel Jurassic World: Evolution both portray the Ceratosaurus as a more aggressive hunter which will prey on humans if they are available.

Behind the Scenes

It was originally thought that the CGI model of the Ceratosaurus resembled that of the Tyrannosaurus, and as a result the Ceratosaurus was actually considered to be a mutant by the majority of the Jurassic Park fandom. It was classified as Ceratosaurus “mutatus” (x Tyrannosaurus); it was inferred that InGen may have filled in the gaps in the Ceratosaurus genome with tyrannosaur DNA. However, this was entirely speculative and is considered inaccurate now, as the Ceratosaurus from the Jurassic Park /// dinosaur charts show that this line of thought was wrong. We are therefore left to believe that it is, indeed, Ceratosaurus nasicornis that is present on Isla Sorna with no clear indications that it was a mutated species or not.